<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>05基本选择器</title>
</head>
<body>
    
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li id="four">4</li>
        <li>5</li>
        <li class="green">6</li>
        <li class="green">7</li>
        <li>8</li>
        <li>9</li>
        <li>10</li>
    </ul>

    <div class="green">111</div>
    <div class="green">111</div>
    <div class="green">111</div>
    <div class="green">111</div>


    <script src="../jquery-3.2.1.js"></script>
    <script>
    
        $(function(){
            $("#four").css("color","red");     // id选择器
            
            $("li.green").css("color","green");

            $("li").css("fontSize","25px");

            // 交集 并集
            $("#four,li.green").css("backgroundColor","pink");
        });
        
    
    </script>
</body>
</html>